Apparatus for calibrating pipes

ABSTRACT

Apparatus for calibrating pipes by expansion or swaging, comprises a housing holding an annular deforming tool consisting of a number of axially extending segments which are arranged side-by-side to form a cylinder and which are movable radially outwards or inwards, this radial movement being limited by stops which engage the ends of the segments, and a cylindrical sleeve which bears on either the inner or the outer faces of the segments and which forms a pressuretight chamber between itself and the housing, so that, in use, when the chamber is supplied with fluid under pressure the sleeve is forced radially outwards or inwards, hence forcing the segments radially outwards or inwards into engagement with the inside or outside of a pipe until further radial movement is prevented by the stops, at which time the pipe is expanded or swaged to an exact size determined by the apparatus.

United States Patent 3,344,634 10/1967 Ellenburg 442,579 12/1890 Grimes3,461,712 8/1969 l-lenkel et al inventors Ali BindernagelDusseldorf-Gerresheim;

Erwin Kost, Osterath; Karl-Hans Staat,

Homberg Bie Ratingen, Germany Appl. No. 754,759

APPARATUS FOR CALIBRATING PIPES l 1 Claims, 13 Drawing Figs.

U.S. CI 1 72/393, 72/402 Int. Cl B21d 39/08 Field of Search 72/58, 393,394, 399, 402, 400, 60-63 References Cited UNITED STATES PATENTS PrimaryExaminer-Richard J. Herbst Assistant Examiner-Michael J. KeenanAttorneys-Curt M. Avery, Arthur E. Wilfond, Herbert L.

Lerner and Daniel J. Tick ABSTRACT: Apparatus for calibrating pipes byexpansion or swaging, comprises a housing holding an annular deformingtool consisting of a number of axially extending segments which arearranged side-by-side .to form a cylinder and which are movable radiallyoutwards or inwards, this radial movement being limited by stops whichengage the ends of the segments, and a cylindrical sleeve which bears oneither the inner or the outer faces of the segments and which forms apressuretight chamber between itself and the housing, so that, in use,when the chamber is supplied with fluid under pressure the sleeve isforced radially outwards or inwards, hence forcing the segments radiallyoutwards or inwards into engagement with the inside or outside of a pipeuntil further radial movement is prevented by the stops, at which timethe pipe is expanded or swaged to an exact size determined by theapparatus.

Patented May 25,1971 3,580,020

P atented May 25, 1971 3,580,020

10 Sheets-Sheet 2 Fig.2

7 A N- h Fig. 2a

Patented May 25, 1971 3,580,020

10 Sheets-Sheet 5 Fig.3

Patented May 25, 1971 10 Sheets-Sheet 5 Patented May 25, 1971 10Sheets-Sheet 6 Patented May 25, 1971 10 Sheets-Sheet 7 S V R PatentedMay 25, 1971 10 Sheets-Sheet 8 :A\\ m w a M \& hh S Q? Patented May 25,1971 3,580,020

10 Sheets-Sheet 9 Patented May 25, 1971 3,580,020

10 Sheets-Sheet 1O 0. LII/1," 0 o J I M m I Fig.10

' 10a a I00 I Fig. ll I16 5 5 APPARATUS FOR CALIBRATING PIPES Thedeviations of the roundness from an exact circular section of pipeswhich are unavoidable in the production of large pipes, are frequentlyso great that satisfactory welding together of pipe sections ofnominally equal diameter is not possible. For this reason such pipes aremechanically brought to an equal intended diameter and exact roundnessby expansion or swaging, called calibration.

Since conformity of the mutually abutting pipe ends is sufficient forsatisfactory welding together of pipe sections, calibration is oftenlimited to relatively short lengths at the ends of the pipe sections.However the necessity can also arise for pipes to be permanentlyexpanded or swaged by a specific amount over the entire length, forexample for the strainhardening of the pipe material, and in the case ofwelded pipes for the reduction of the welding stresses or in order toachieve smooth-walled pipe conduits.

In the following description of the invention, by calibration there isto be understood not only a variation of the pipe diameter bypredetermined amounts .for the purpose of achieving precise pipediameters, but any variation of pipe diameter with simultaneouscorrection of form if necessary.

Various forms of apparatus are known for calibrating pipes, especiallypipe ends. One form has a deforming tool which consists essentially ofan externally cylindrical bush, divided by axial planes into a number ofsegments-as many as with a tapered bore and an axially displaceablemandrel of frustopyramidal form having a number of sides correspondingto the number of segments, with radial and axial stops for the segments.Such a calibrating apparatus is secured on a stand which is displaceableand securable on base frame. It has the disadvantage that the surfacepressure exerted by the tapered inner surfaces of the segments upon theside surfaces of the frustopyramidal mandrel is greater by the ratio ofthe mandrel diameter to the pipe diameter than the radial pressure ofthe outer segment surfaces upon the pipe wall necessary for expansion.Furthermore, on account of the inclination of the tool surfaces slidingon one another in displacement towards the mandrel axis, the radialpressure between them increases over the length of the calibre segmentsfrom the large end face to the smaller end face of the frustopyramidalmandrel, in inverse proportion to the end surface diameters.

in the expansion of pipes by drawing the mandrel into the axiallysupported calibre bush, the danger exists that when a certain expansionpressure is exceeded the surface pressure between the surfaces of thebush and the mandrel sliding on one another may become too great andthese parts of the apparatus wear prematurely and tend to seize, thisbeing helped by any dust and dirt which have penetrated. Similardifficulties occur in the disengagement of the tool from the workpiece.These phenomena are the reason why expansion devices of this kind areoperated only with relatively small surface pressures and are used onlyfor the calibration of pipes of materials of low strength and havingsmall wall thicknesses in relation to the diameter.

A further essential disadvantage of the apparatus consists in that thecalibre segments, rounded-off externally according to the final internaldiameter of the pipe, rest at the beginning of the expansion operationonly with their longitudinal edges on the inner wall of the pipe andcome gradually into full abutment with the pipe inner wall only withincreasing expansion, with the consequence that in the region of theseedges the flow limit of the pipe material is exceeded sooner than in thepipe wall parts lying between them so that an irregular materialexpansion is produced over the pipe periphery. Consequently with thisapparatus expansion of the pipe periphery for the purpose of materialstrengthening is not possible, since for this purpose a uniform materialexpansion must be required over the full periphery.

Since data as to pipe dimensions always relate to the external diameterand pipes of equal nominal diameter can have wall thicknesses differingconsiderably from one another, furthermore, for the expansion of pipesof given external diameter, special calibre bushes are needed for eachpipe wall thickness, since otherwise the pipes do not become uniformlyround.

In another form of known apparatus, for the expansion of pipes overtheir entire length a pressure liquid is pumped into the pipe which issealed at the ends, the occurrence of inaccuracies of roundness isavoided due to the fact that a cylindrical mould of length correspondingto the pipe length is arranged around the pipe, and the pipe is expandeduntil it uniformly abuts the inner wall of the mould. With thisapparatus the pipe is also tested at the same time for fluidtightness.This apparatus is not capable of working without the outer mold since onthe use only of internal pressure an irregular deformation and nonroundpipes would result from inequalities of the wall thickness and of thematerial flux.

This expansion and calibrating apparatus has the further disadvantagethat an external mould of length corresponding to the pipe length mustbe available for every pipe diameter and a considerable quantity ofliquid must be available for the filling of the pipes.

Moreover, the use of the apparatus requires much time both for thepreparation of the individual expansion operations by sealing off andintroduction of the pipe to be expanded into the mould cylinder, for theconnection of the liquid conduits, the filling and emptying of the pipeand for the pressing off and expansion itself. Use of this apparatus onbuilding sites where pipes are laid and connected into conduits ishardly possible on account of its dimensions, its weight and thecircumstances connected with its operation.

According to this invention an apparatus for the calibration of pipes byexpansion or swaging comprises a housing holding an annular deformingtool consisting of a number of axially extending segments which arearranged side by side to form a cylinder and which are movable radiallyoutwards or inwards, this radial movement being limited by stops whichengage the ends of the segments, and a cylindrical sleeve which bears oneither the inner or the outer faces of the segments and which forms apressuretight chamber between itself and the housing, so that, in use,when the chamber is supplied with fluid under pressure the sleeve isforced radially outwards or inwards, hence forcing the segments radiallyoutwards or inwards into engagement with the inside or outside of a pipeuntil further radial movement is prevented by the stops, at which timethe pipe is expanded or swaged to an exact size determined by theapparatus.

In contrast to the previous apparatus, that of the present invention canbe used to calibrate pipes at comparatively low expense, is relativelysmall and light, the parts of which are hardly subject to wear inoperation, which is simple to operate, permits a rapid manner of workingand produces better results.

When the apparatus is in the form of an expansion apparatus the annularsleeve bears upon the inner surfaces of the segments and the pressure isapplied to the sleeve from the interior; whereas when the apparatus is aswaging apparatus the sleeve encloses the cylindrical tool assembledfrom the segments and the pressure is applied to the outer side of thesleeve.

In order to ensure reliable and rapid lifting away of the deforming toolfrom the workpiece again after every working stroke, the segments arepreferably biased permanently, or are arranged to be biased temporarily,radially in an opposite direction to that in which they are moved whenthe chamber is pressurized. In the case of a swaging apparatus thisreturn bias may be supplied by leaf springs inserted into the gapsbetween adjacent segments of the deforming ,tool. Preferably the housinghas a pair of annular flanges which abut the opposite ends of thesegments and form guides for the radial movement of the segments, andeach segment has at each of its ends a shoulder which projects into anannular groove in the adjacent housing flange, one of the axiallyextending walls of each groove forming a' stop which engaged by theshoulders to limit the operative movement of the segments.

In this case a permanently acting return bias can be applied asyieldable force by a tension or compression spring initially stressed inthe peripheral direction and bearing upon the shoulders at the ends ofthe segments. A temporarily acting return bias may be provided by eachshoulder having a radially extending flange which projects into anannular recess in the wall of the groove which forms the stop, anannular seal extending round the radially extending flanges and forminga pressuretight chamber within the recess, this chamber beingpressurized to return the segments when the pressure in the chamberbetween the housing and the sleeve is relaxed.

In the case. of variation of the pipe diameter on only a part of thepipe length, in order to provide a gradual transition from the defonnedpipe part to the underformed pipe part, the segments may be bevelled atone end of the deforming tool.

Thus the feed movement of the workpiece to the tool is at the same timefacilitated.

The axial extension of the part of the segments defined by axiallyparallel longitudinal edges corresponds at least to the pipe end to bereshaped to precise diameter and exact roundness. Such an apparatus ofshort constructional length in comparison with the pipe length can alsobe used for the reshaping of pipes over their whole length if they and aholding device for the pipe are arranged to move relatively to oneanother in the axial direction.

Such an apparatus intended for the expansion of pipes would have to besecured on the free end of a sufficiently long overhang arm which isclamped at one end on a support, and which is movable with the apparatusintermittently into the pipe to be expanded, or intermittently over thepipe if the pipe is to be swaged.

An apparatus for swaging pipes may be arranged in a fixed or axiallymobile housing which is open at both ends, through which the pipe ispushed intermittently, or which is itself intermittently moved over thepipe which is held fast at one end.

The apparatus may also include an abutment for the pipe part to bedeformed, the abutment taking up the deformation pressure anddetermining the final form of the pipe, and consisting either of a ringcoaxially surrounding and spaced from the deforming tool or of a mandrelarranged coaxially within and spaced from deforming tool.

Various examples of apparatus in accordance with the present inventionare now described with reference to the accompanying drawings, in which:

FIG. 1 is an axial longitudinal section through one-half of one exampleof an apparatus for calibrating pipes by expanslon;

FIG. 2 represents a partial cross section through the apparatus shown inFIG. 1 along the line A-A;

FIG. 2a represents a plan view of the externally visible part of severalsegments of the deforming tool of the apparatus shown in FIGS. I and 2;

FIG. 3 is a similar view to that of FIG. 1, but showing the apparatuswith an abutment ring surrounding the deforming tool;

FIG. 4 is a similar view to that of FIG. I but showing a further examplefor calibrating pipes by expansion;

FIG. 5 is an axial longitudinal section through one-half of an exampleof an apparatus for calibrating pipes by swaging;

FIG. 6 is a similar view to that of FIG. 5, showing the apparatus withan abutment mandrel arranged within the deforming tool of the apparatus;

FIG. 7 is a similar view to that of FIG. 5, but showing a furtherexample;

FIG. 8 is a longitudinal section showing the apparatus of FIG. 4together with a sealing and clamping head attached to a pipe end to testpressuretightness of the pipe;

FIG. 9 is a side elevation, in part longitudinal section, of an exampleof an apparatus for the expansion of pipes in which the pipe can bemoved step by step over the expansion apparatus; 7

FIG. 10 is a similar view to that of FIG. 9, but showing an example ofan apparatus for swaging pipes;

FIG. 11 illustrates an example of an apparatus for swaging pipes, inwhich the swaging device is arranged on a frame which is movable in anaxial direction along a unilaterally firmly clamped-in pipe; and

FIG. 12 shows an example of an apparatus for the simultaneouscalibration of both ends of a pipe in which a calibrating apparatus ispushed on to each of the ends of the pipe which is supported in themiddle.

In the example shown in FIGS. 1, 2 and 2a, the deforming tool consistsof a number of segments 1, which form a cylinder around the cylindricalbody 4, with thin leaf springs 2 or 2 inserted as spacing members intothe gaps between them, which lie in axial planes. The segments 1 andleaf springs 2, 2' have shoulders at their ends lawhich project withmutually facing annular grooves 4b, 5b in annular flanges 4a, 5extending radially from the external periphery of the housing body 4. Acylindrical sealing sleeve 3 of rubber-elastic material lies against theinner surfaces of the segments 1 and leaf springs 2, with its endsbearing tightly against the end faces of the guide grooves 4b, 5b andforms with the peripheral surface 40 of the housing body 4 an annularchamber 30 of variable volume tightly closed off on all sides. Thischamber can be served with a fluent material under pressure through apassage 7 in the body 4. Tensioned annular springs 6 countersunk on theshoulders In of the segments I urge the segments radially inwards intotheir rest position in which their outer surfaces lie flush with theperipheries of the flanges 4a, 5. However, when the chamber 3a ispressurized the sleeve 3 and hence the segments 1 are pushed radiallyoutwards, the segments engaging the part of a pipe 10 which is pushedover the flanges 4a, 5. The maximum amount by which the pipe part isthen expanded on further pressurizing the chamber 3a is determined bythe width of the grooves 4b, 5b, the outer axially extending walls ofwhich serve as stops for the segment shoulders la, and hence for thesegments themselves. After the removal of the pressure from the chamber311 the springs 6 return the segments 1 into their initial rest positionagainst the force of the leaf springs 2, 2' lying between them. Thehousing 4, 5 is secured on the free end of an overhang arm 8 which isclamped at its other end to a support and which is sufficiently long fora pipe to be expanded along its whole length by pushing it bit by bitover the expanding apparatus, provided that the part 10a to be expandedis longer than the effective length of the segment 1.

If only pipe ends corresponding to or shorter than the length of thesegments 1 are to be expanded, a stop 4d, which may be adjustable is theaxial direction, can be provided on the periphery of the housing flange4a.

The other housing flange 5 consists for reasons of assembly of a ring 5detachably connected with the housing body 4, the ring being sealed withthe latter by packing rings 50.

In the example shown in FIG. 3 the apparatus in FIGS. 1, 2, 2a is fittedwith an abutment ring 9 which surrounds the housing 4, 5 and forms anannular gap between it and the housing for receiving the pipe to beexpanded. The inner diameter of the ring 9 is the same as the externaldiameter to which the pipe is to be expanded. The ring 9 can be arrangedin common with the support for the overhang arm 8 on a chassis which iseither fixed or mobile in the axial direction (not shown).

The calibrating apparatus shown in FIG. 4 differs from that shown inFIGS. 1 and 2 essentially only in that the segments 41 and the sealingsleeve 43 are not returned by springs but hydraulically or pneumaticallyinto their rest position after pressure is released from the chamber430. For this purpose the shoulders 41a of the segments 41 are providedwith annular radially outwardly extending flanges 41b which project intoannular recesses 46a in the outer walls of the grooves receiving theshoulders 41a. In the recesses 460 the flanges 41b are surrounded by aU-shaped se sling sleeve 46. The segments 41 are returned into theirrest position by gas or liquid pressure introduced after every workingstroke into the annular recesses 46a behind the sealing sleeves 46.

The annular recesses 46a are connected through passages 45b, 44b andconduits 40a and 40b with a container 40 which is filled with gas orliquid under pressure. In every expansion operation the fluid isexpelled from the annular recesses 46a into the container 40, from whichit flows back into the annular recesses 46a after relaxation of theexpansion pressure and moves the segments 41 with the sleeve 43 backinto their rest position.

' The housing of the apparatus shown in this example consists, forconstructional reasons, of several detachably interconnected parts.Flange rings 45 with interposed packing rings 45a are placed upon bothends of an externally cylindrical body 44. Ring nuts 49 with inwardlydirected flanges 4% which, together with the mutually facing end facesof the rings 45 form the annular recesses 46a, are screwed on to theflange rings 45.'The inner peripheral surfaces of the flanges 49b hereform the outer stops for the shoulders 41a of the segments 41. The rings45 are sealed with the ring nuts outside the openings of the passages45b by packing rings which ensure a pressuretight closure for theannular recesses 46a. The introduction of fluid under pressure into thechamber 450 takes place through a radial passage 47 in the body 44. I

The expanding apparatus shown in FIG. 4 is in fact more expensive toconstruct than those shown in FIGS. 1 and 3, but offers the advantagethat the retraction of the deforming tool proceeds substantially morequickly and consequently more working strokes in a set time can beobtained. The quicker manner of operation has an especially favorableeffect in the calibration of relatively large pipe lengths.

The apparatus shown in FIG. 5 is intended for the calibration of pipesby swaging. The segments 51 here lie with the sleeve 53 externallyenclosing them in an inner recess of the housing 54 which is limited atone end by an inwardly directed flange 54a of the housing 54 and at theother end by a ring 55 pushed into the end of the housing 54. Betweenthe sleeve 53 and the housing 54 is formed a pressuretight chamber 53a.Annular flanges 54b and 55b projecting axially towards each other fromthe flange 54a and the ring 55 respectively form guides for the endedges of the segments 51 and stops for the shoulders at sector ends 510.Fluid under pressure is supplied to the chamber 530 through a bore 540in the housing body 54.

Sealing rings 55a between the housing body 54 and the ring 55 preventthe escape of fluid from the pressure chamber 53a.

The calibrating apparatus shown in FIG. 6 differs from the example ofFIG. 5 only in that an abutment mandrel 60 for'the pipe 10 to bedeformed is arranged coaxially with the housing 54, 55. This mandreldetermines the internal diameter of the pipe part 10b which is to bedeformed. The return of the segments 1 is effected here by the leafsprings 2 arranged between them (similar to those shown in FIGS. 2, 2a).To support and assist in returning the segments, outwardly actingannular springs 66, are arranged on the shouldered ends of the segments51. The abutment mandrel 60 is secured on an overhang arm 68. v

In the example of calibrating apparatus shown in FIG. 7, which otherwisecorresponds to the example shown in FIG. 5 or 6, the return force of theleaf springs 2, 2 is supplemented in a manner corresponding to that inthe example of FIG. 4, i.e. by hydraulic or pneumatic pressure whichacts in annular recesses 760 through U-shaped sealing sleeves 76, 76accommodated therein upon annular flanges extending inwardly from theshoulders of the segments 71. Here again for construction reasons thehousing is assembled from several parts 74, 75, 79 sealed from oneanother by sealing rings. The pres sure chambers 76a behind the sealingsleeves 76 resting on the shoulders 710 are connected, like the pressurechambers 460 shown in FIG. 4, to a pressurized container (40) fluid.

FIG. 8 shows a particular example of an expanding apparatus with thefeatures of the present invention, which permits, together with thecalibration of pipe ends, the testing of pipes for fluidtightness andstrength by the introduction of fluid under pressure into the pipe whichis closed tightly at both ends. The apparatus is assembled substantiallylike that shown in FIG. 3. However, here the annular gap receiving thepipe end 105 to be expanded, between the abutment ring- 89 and thehousing 84, 85, is closed off at one end by an end plate 82 bolted tothe ring 89 and the housing body 84. The housing body 84 is providedwith a connection 840 for the test pressure liquid conduit. A packingring 85c lies in a peripheral groove of the flange ring 85, and isforced against the inner wall of the pipe 10 by the pressure of fluidintroduced behind it through passages 84b, 85f, and 85d.

In the example represented diagrammatically in FIG. 9 a completeapparatus for the expansion of pipes is shown the expansion apparatusbeing secured on the free end of a fixed overhang arm 98. An abutmentring 99 surrounding the apparatus 90 is fixed onto an immovable chassis96. In front of and behind the expanding apparatus 90 there areresiliently supported rollways 94, 95, by means of which a pipe 10 to beexpanded can be fed to the apparatus 90 and if desired moved over it.

In the example shown in FIG.10, calibrating apparatus 100 for swagingpipes is arranged in a fixed housing 106. An abutment mandrel 60 issecured on the free end of a fixed overhang arm 8. Here againresiliently supported rollways 104, serve for the feed of a pipe 10 tothe calibrating apparatus 100 and possibly for the intermittent furthermovement of the pipe between the indiw'dual reshaping operations.-

In the example shown in FIG. 11 a calibrating apparatus is arranged withits housing 116 on a trolley 114 which is mobile in the axial direction,with the aid of which it can be shifted on to the pipe 10 to-be reshapedwhich is fixed on a retaining device 115. A calibrating mandrel 60secured on an overhang arm 108 of appropriate length is also mountedonthe trolley 1l4-and is moved along the pipe with the calibratingapparatus. The mandrel 60 is axially displaced against a spring 116 onstriking the retaining device 115.

The apparatus represented diagrammatically in FIG. 12 enables thesimultaneous calibration of both ends of a pipe 10. Two calibratingapparatuses 120 are arranged with their housing 126 on trolleys 124which are mobile in the axial direction in relation to a device 125 forresiliently supporting and holding the middle part of the pipe 10.Calibrating 'mandrels 128 are also mounted on the trolleys 124.

In place of the apparatuses 100, 110, 120 represented in the examplesshown in FIGS. 10, 11 and 12, for swaging pipes apparatuses for theexpansion of pipes may be used instead, even those which-as for examplethe apparatus shown in FIG 8- -are also used for the testing of pipesfor fluidtightness.

In all the examples shown in the drawings, at one end of the deformingtool the ends of the segment faces remote from the faces on which thesleeve acts are bevelled, i.e. tapered towards the end of the tool, sothat in operation a gradual transition from the deformed pipe part 18the undeformed part is obtained.

We claim:

1. Apparatus for calibrating pipes by expansion or swaging, comprising ahousingformed with a pair of spaced annular flanges, and an annulardeforming tool held on said housing, said deforming tool comprising amultiplicity of axially extending segments each having a radialdimension greater than the circumferential dimension thereof and havinga relatively narrow spacing from one another, means mounting saidsegments on said housing side by side in the space between said annularflanges to form a cylinder and so that said'segments are movableradially with respect to said housing, stop means for engaging the endsof said segments to'limit the radial movement of said segments,cylindrical sleeve means located within said space between said annularflanges and being in sealing engagement at the respective ends thereofwith said annular flanges, said sleeve means bearing on one of the facesof said segments and defining a pressuretight chamber between itself andsaid housing, and means for supplying fluid under pressure to saidchamber, whereby, when said chamberis supplied with fluid underpressure, said sleeve and hence said segments are forced to moveradially away from said housing into engagement with the wall of a pipeplaced radially adjacent said housing and deform said pipe in thevicinity of said segments until further radial movement is prevented bysaid stop means, at which time said pipe is deformed to an exact sizedetermined by the apparatus.

2. Apparatus as set forth in claim 1, for calibrating pipes byexpansion, wherein said cylindrical sleeve means on the inner faces ofsaid segments and when said fluidtight chamber between said sleeve andsaid housing is supplied with fluid under pressure, said sleeve andhence said segments are forced radially outwards to expand said pipewhich is placed over said housing.

3. Apparatus as set forth in claim 1, for calibrating pipes by swaging,wherein said cylindrical sleeve means bears on the outer faces of saidsegments and when said fluidtight chamber between said sleeve and saidhousing is supplied with fluid under pressure, said sleeve and hencesaid segments are forced radially inwards to swage said pipe which isplaced within said housing.

4. Apparatus as set forth in claim 1, wherein leaf springs are positionbetween adjacent members of said plurality of segments so that saidsegments are held evenly in place peripherally around the cylinder whichthey form.

5. Apparatus as set forth in claim 1, wherein at one end of saiddeforming tool the ends of the faces of said segments remote from thefaces on which said sleeve bears are tapered towards said end of saiddeforming tool.

6. Apparatus as set forth in claim 1, including means biasing saidsegments radially in a direction opposite to that in which they aremoved when said fluidtight chamber is supplied with fluid underpressure, for returning said segments to their rest positions when saidfluid pressure is removed from said fluidtight chamber.

7. Apparatus for calibrating pipes by either one of expansion andswaging, comprising a housing, and an annular deforming tool held onsaid housing, said deforming tool consisting of a plurality of axiallyextending segments, means mounting said segments on said housing side byside to form a cylinder and so that said segments are movable radiallywith respect to said housing, stop means for engaging the ends of saidsegments to limit the radial movement of said segments, cylindricalsleeve means bearingon one of the faces of said segments and defining apressuretight chamber between itself and said housing, means forsupplying fluid under pressure to said chamber, whereby, when saidchamber is supplied with fluid under pressure, said sleeve and hencesaid segments are forced to move radially with respect to said housinginto engagement with the wall of a pipe placed radially adjacent saidhousing and deform said pipe in the vicinity of said segments untilfurther radial movement is prevented by said stop means, at which timesaid pipe is deformed to an exact size determined by the apparatus,means biasing said segments radially in a direction opposite to that inwhich they are moved when said fluidtight chamber is supplied with fluidunder pressure, for returning said segments to their rest positions whensaid fluid pressure is removed from said fluidtight chamber, saidhousing being provided with a pair of annular radially extendingflanges, mutually facing faces of said flanges abutting the oppositeends of said segments and forming guides for the radial movement of saidsegments, and each of said mutually facing faces containing wall meansdefining an annular groove, and each of said segments being provided ateach of its ends with shoulder means which project into said annulargrooves, the axially extending walls of said wall means defining saidannular grooves remote from said cylindrical sleeve forming said stopmeans.

8. Apparatus as set forth in claim 6 wherein said biasing means actsupon said shoulders at the ends of said segments.

9. Apparatus as set forth in claim 7, wherein each of said axiallyextending walls fonning said stop means contains further wall meansdefining an annular recess, said shoulders at each end of said segmentsbeing provided with a radially extending flange pro ecting into thecorresponding annular recess, an annular seal means extends around saidradially extending flange in said annular recess and forms apressuretight chamber within said recess, and there is provided meansfor supplying fluid under pressure to said chamber in each of saidannular recesses when the pressure in said chamber between said housingand said cylindrical sleeve is released, so that said segments arereturned to their rest positions.

10. Apparatus as set forth in claim 1, including a cylindrical abutmentsurface coaxial with said cylinder formed by said segments and spacedradially apart from the operative faces of said segments of saiddeforming tool, the annular gap between said segments and said abutmentsurface receiving said pipe to be calibrated.

11. Apparatus as set forth in claim 10, including means for tightlyclosing said annular gap between said segments and said abutment surfaceat one end, means defining an annular groove in the peripheral surfaceof said housing at the other end of said annular gap, an annular packingring in said annular groove, and means for supplying fluid underpressure to the bottom of said annular groove to force said packing ringoutwards with respect to said groove against a pipe which is insertedinto said annular gap to form a seal so that said pipe can be tested forfluidtightness at the same time as it is calibrated.

1. Apparatus for calibrating pipes by expansion or swaging, comprising ahousing formed with a pair of spaced annular flanges, and an annulardeforming tool held on said housing, said deforming tool comprising amultiplicity of axially extending segments each having a radialdimension greater than the circumferential dimension thereof and havinga relatively narrow spacing from one another, means mounting saidsegments on said housing side by side in the space between said annularflanges to form a cylinder and so that said segments are movableradially with respect to said housing, stop means for engaging the endsof said segments to limit the radial movement of said segments,cylindrical sleeve means located within said space between said annularflanges and being in sealing engagement at the respective ends thereofwith said annular flanges, said sleeve means bearing on one of the facesof said segments and defining a pressuretight chamber between itself andsaid housing, and means for supplying fluid under pressure to saidchamber, whereby, when said chamber is supplied with fluid underpressure, said sleeve and hence said segments are forced to moveradially away from said housing into engagement with the wall of a pipeplaced radially adjacent said housing and deform said pipe in thevicinity of said segments until further radial movement is prevented bysaid stop means, at which time said pipe is deformed to an exact sizedetermined by the apparatus.
 2. Apparatus as set forth in claim 1, forcalibrating pipes by expansion, wherein said cylindrical sleeve means onthe inner faces of said segments and when said fluidtight chamberbetween said sleeve and said housing is supplied with fluid underpressure, said sleeve and hence said segments are forced radiallyoutwards to expand said pipe which is placEd over said housing. 3.Apparatus as set forth in claim 1, for calibrating pipes by swaging,wherein said cylindrical sleeve means bears on the outer faces of saidsegments and when said fluidtight chamber between said sleeve and saidhousing is supplied with fluid under pressure, said sleeve and hencesaid segments are forced radially inwards to swage said pipe which isplaced within said housing.
 4. Apparatus as set forth in claim 1,wherein leaf springs are position between adjacent members of saidplurality of segments so that said segments are held evenly in placeperipherally around the cylinder which they form.
 5. Apparatus as setforth in claim 1, wherein at one end of said deforming tool the ends ofthe faces of said segments remote from the faces on which said sleevebears are tapered towards said end of said deforming tool.
 6. Apparatusas set forth in claim 1, including means biasing said segments radiallyin a direction opposite to that in which they are moved when saidfluidtight chamber is supplied with fluid under pressure, for returningsaid segments to their rest positions when said fluid pressure isremoved from said fluidtight chamber.
 7. Apparatus for calibrating pipesby either one of expansion and swaging, comprising a housing, and anannular deforming tool held on said housing, said deforming toolconsisting of a plurality of axially extending segments, means mountingsaid segments on said housing side by side to form a cylinder and sothat said segments are movable radially with respect to said housing,stop means for engaging the ends of said segments to limit the radialmovement of said segments, cylindrical sleeve means bearing on one ofthe faces of said segments and defining a pressuretight chamber betweenitself and said housing, means for supplying fluid under pressure tosaid chamber, whereby, when said chamber is supplied with fluid underpressure, said sleeve and hence said segments are forced to moveradially with respect to said housing into engagement with the wall of apipe placed radially adjacent said housing and deform said pipe in thevicinity of said segments until further radial movement is prevented bysaid stop means, at which time said pipe is deformed to an exact sizedetermined by the apparatus, means biasing said segments radially in adirection opposite to that in which they are moved when said fluidtightchamber is supplied with fluid under pressure, for returning saidsegments to their rest positions when said fluid pressure is removedfrom said fluidtight chamber, said housing being provided with a pair ofannular radially extending flanges, mutually facing faces of saidflanges abutting the opposite ends of said segments and forming guidesfor the radial movement of said segments, and each of said mutuallyfacing faces containing wall means defining an annular groove, and eachof said segments being provided at each of its ends with shoulder meanswhich project into said annular grooves, the axially extending walls ofsaid wall means defining said annular grooves remote from saidcylindrical sleeve forming said stop means.
 8. Apparatus as set forth inclaim 6 wherein said biasing means acts upon said shoulders at the endsof said segments.
 9. Apparatus as set forth in claim 7, wherein each ofsaid axially extending walls forming said stop means contains furtherwall means defining an annular recess, said shoulders at each end ofsaid segments being provided with a radially extending flange projectinginto the corresponding annular recess, an annular seal means extendsaround said radially extending flange in said annular recess and forms apressuretight chamber within said recess, and there is provided meansfor supplying fluid under pressure to said chamber in each of saidannular recesses when the pressure in said chamber between said housingand said cylindrical sleeve is released, so that said segments arereturned to their rest positions.
 10. Apparatus as set forth in claim 1,includIng a cylindrical abutment surface coaxial with said cylinderformed by said segments and spaced radially apart from the operativefaces of said segments of said deforming tool, the annular gap betweensaid segments and said abutment surface receiving said pipe to becalibrated.
 11. Apparatus as set forth in claim 10, including means fortightly closing said annular gap between said segments and said abutmentsurface at one end, means defining an annular groove in the peripheralsurface of said housing at the other end of said annular gap, an annularpacking ring in said annular groove, and means for supplying fluid underpressure to the bottom of said annular groove to force said packing ringoutwards with respect to said groove against a pipe which is insertedinto said annular gap to form a seal so that said pipe can be tested forfluidtightness at the same time as it is calibrated.